Dental device and method of utilizing same



Oct. 17, 1939,. J, g'RENsCJNl 2,176,575 I DENTAL DEVICE AND METHOD 0F UTILIZING SAME Filed March 2o, 1937 ATToRNEy Patented Oct. 17, 1939 UNETED; STATES PATENT OFFICE ING SAME

James Sorenson, Fond du Lac, Wis.

Application March 20,

Claims.

My present invention relates in general to improvements in the art of prosthodontia, and relates more specically to an improved method of and apparatus for locating the true anatomical centric and vertical relation of the mandible to the maxilla in the construction of artificial dentures.

Generally defined, an object of my present invention is the provision of an improved dental device and anfimproved method of utilizing the same.

In the production of prosthetic dentures, and in order to reestablish the esthetics, normal expression, comfort and proper functioning and oclli clusion of the teeth, it is necessary to reproduce because they necessitate locking of the bite plates' as accurately as possible the original maxillamandibular relationship, commonly designated as the bite. ln order to thus restore the true bite, it is desirable to rst determine the correct vertical stopping place of the mandible so that all of the muscles may function most efficiently and normal facial expression will result. It is also desirable to obtain the true centric position of the mandible where the heads of the condyles are properly positioned in the most retruded point in the glenoid fossa, in order that teeth may be articulated on the dentures in such a manner that a lateral or protrusive strain will not be exerted in the act of biting hard in the closed bite. It is moreover necessary to provide for locking the bite plates in the true centric and vertical relation with equalized pressure on the bearing ridges and in such a manner that the correct maxilla-mandibular relation may always be relocated and assured after mounting on the articulator. While various methods of establishing and of determining one or more of these desirable factors, have heretofore been proposed, they are all relatively unsatisfactory either because they require the tracing of a perfect Gothic arch, or

exactly at the apex of the arch. None of the prior methods and apparatus, which utilize the Gothic arch method of determining centric relation are applicable with any degree of accuracy to cases where conditions exist which make it impossible for the patient to trace a definite Gothic arch during normal movement of the mandible, and all of the previous instrumentalities for determining centric bite involve considerable guesswork and possible error under many conditionsof use.I It is therefore a more specic object of my present invention to provide an improved method of accurately and positively locating or determining the true centric bite of any patient, re-

1937, Serial No. 131,980

gardless of the existence of unusual and abnormal conditions which tend to prevent tracing of a satisfactory Gothic arch, or of the fact that the natural teeth may have been previously extracted.

Another specific object of my invention is to provide simple, compact and readily manipulable apparatus for carrying on my improved method, and for also accurately determining the correct stopping place for the mandible with respect to the maxilla.

A further speciiic object of the invention is the provision of an improved method and apparatus for deinitely locating the true anatomical centric and vertical relation ofthe mandible to the maxilla, quickly and Without resorting to guesswork.

Still another specific object of this invention is to provide an improved dental device for facilitating correct construction of articial dentures, which is relatively inexpensive, which has a wide range of use in order to meet different anatomical conditions, and which may be readily utilized to accomplish accurate results.

An additional specic object of my invention is to provide an improved method and dental device for locating the true centric occlusion of the mandible to the maxilla by having a Gothic arch traced on the inclined plane of a transverse abutment on the tracer plate.

A further object oi my invention is to provide an apparatus by which the true centric bite may be positively determined by the adjustment of the tracer pin to a transverse line or abutment on a tracer plate, from which point tracings can only be made rearwardly if the true centric relation has been established.

Another object of my invention is to provide a centric bite determining device, in which the tracer pin will rest at the lower edge of a transverse inclined plane in the centric bite and in the act of locking the bite plates, and wherein the inclined plane will guide the pin to centric occlusion in the same manner that the cusps of the natural teeth will do in the mouth.

Still another specic object of my invention is to provide a device which can be used to accurately establish the centric bite in the retruded position of the mandible, yand which can also be used for taking check bites that will show the inclination of the condyle paths in retrusive or lateral bites, in the relative position of the mandible to the maxilla which will correspond to the further functioning of the dentures.

A further specific purpose of my invention is to provide a device for recording the centric retrusive, protrusive and lateral bites under conditions approximating the function of the natural anatomical teeth, by providing a tracer plate with an anterior area for locating the centric bite on and an inclined plane leading up to a raised anterior area for registering the condyle paths, in the protrusive and lateral bites, the height of the inclination to be determined by the height of the cusps on the teeth that are to be used.

Another object of the invention is to provide an improved method of determining centric bite and other factors, either with intra or eXtra-oral appliances which are readily manipulable without undue annoyance to the patient.

An additional speciiic object of my invention is the provision of improved apparatus which will enable any dentist to secure registration of the true centric bite of any patient regardless of the existence of abnormal anatomical conditions between the condyles and the Vglenoid fossa, or of unnatural muscular readjustments.

These and other specic objects and advantages will be apparent from the following detailed description.

A clear conception of the several steps constituting my improved method, and of the mode of constructing and of utilizing the improved dental apparatus which is used in carrying on this method, may be had by referring to the drawing accompanying and forming a part of this specication wherein like reference characters designate the same or similar parts in the various views.

Fig. 1 is a central vertical section through `fragments of the mandible and maXilla of a patient, showing one form of the improved apparatus applied to the patients gums;

Fig. 2 is a bottom view of the maxillular portion of the apparatus shown in Fig. 1;

Fig. 3 is a top view of the mandibular portion of the apparatus of Fig. 1

Fig. l is a central vertical section through the upper or maxillular portion of the'apparatus,

- showing the adjustable tracer pin being removed from its normal support; Y

Fig. 5 is a top view of the adjustable tracer pin and its supporting plate, removed from upper bite block;

Fig. 6 is a bottom view of a modifiedy type of tracer pin and supporting plate assemblage;

Fig. 7 is a central vertical section through the assemblage of Fig. 6, taken along the line Fig. 8 is a top view of the modied tracer pin and supporting plate assemblage of Figs. 6 and 7;

Fig. 9 is a top View of a modified lower tracer plate; and

Fig. l is a side view of the modied tracer plate of Fig. 9.

While my invention has been shown and described herein as having been embodied in several spec-ic types of apparatus especially applicable to certain classes of patients, it is not the intent to thereby unnecessarily restrict the scope since some of the steps of the improved method and some of the improved structural features are more generally applicable.

Referring specically to Figs. l to inclusive of the drawing, the improved dental apparatus shown therein comprises in general, a tracer pin I4 mounted for vertical adjustment in a block I5 which is in turn mounted for horizontal forward and rearward adjustmentl along an upper substantially'horizontal supporting plate I5; and

a lower tracer plate I'I having anterior and posterior areas I8, I9 respectively, separated by a transverse division line or abutment in the form of an inclined portion 20 which constitutes a part of the posterior plate area. The upper pin supporting plate I6 has lateral projections 2l adapted for embedment in or beneath the side ridges 22 of the upper bite block 23 which is ted to the maXillular gums 24 of a patient, and the lower tracer plate Il has similar lateral projections 25 which are likewise adapted to be embedded in the side ridges 26 of a lower bite block 2 fitting the mandibular gums of the patient.

The tracer pin I4 preferably has a hardened tracing point which is directly cooperable with the areas I8, I9 of the lower plate II, and is screw threaded to coact with a threaded central bore in the block I5 so as to permit convenient vertical adjustment of the pin I4 relative to its supporting plate I6 in order to properly position the plates I6, I' to accurately determine the true anatomical height of the teeth. rIhe block I5 is provided with an upper projection forming a head 29 and having a recess 3D directly beneath the head, and the upper supporting plate IB has an elongated slot 3i normally cooperable with the recess 3U to permit horizontal sliding movement of the block I5 along the plateV I5. The front and rear ends of the upper plate I5, are provided with dependingV bearing flanges 32, 33 respectively, having downwardly open journal recesses within which an adjusting 'screw 34 and a guide rod 35 are normally supported as shown in Figs. 1 and 2. The screw 34 and the rod 35 are parallel to each other and pierce the block I5 horizontalls7 on opposite sides of the tracer pin I4, the screw 34 having 'external threads coacting with internal threads in a bore of the block I5 and being provided with an end knob 36 for permitting turning of the sc-rew 34 externally of the patients mouth. The forward end of the slot 3l in the supporting plate I6 has an enlargement 31 as shown in Figs. 4 and 5, through which the head, 29 of the horizontally adjustable block I5 is adapted to be withdrawn downwardly, when the block I5 has been moved forwardly as far as possible by the Screw 34 as shown in Fig. 4, and the pin I4, block I 5, screw 34 and rod 35 may then be removed as a unit from the upper plate I 5. The rod 35 is smooth and coacts with a smooth hole in the block I5, thus merely serving as a guide for the block I5 and pin I4.

The tracer pin supporting assemblage may be of various types including the modified form specically illustrated in Figs. 6, 7 and 8 inclusive. In this modified embodiment of the invention, the tracer pin I4 is vertically adjustably mounted in a two part block I5 which has -a head 29 and grooved portion 3U' slidably cooperable with a slot 3| formed in the upper supporting plate I6. The upper and lower relatively adjustable parts of the block I5 coact with a resilient slide 34 which is guided between spaced lugs 32 formed integral with the front of the plate I6', and has a front manipulating portion 35 normally disposed externally of the patients mouth. The parts of the block I5 may be relatively adjusted to maintain the desired frictional contact between the upper face of the slide 34 and the lower face of the plate I5', and the slot 3| has a front end enlargement 31 through which the head 29' of the block I5 may be withdrawn downwardly in order to remove the pin I4, block I5 and slide 34 from the supporting plate I6' as a unit.

While the lower tracer plate il has been illustrated in Figs. l and 3, as being provided with anterior and posterior dat areas i8, i9 separated by a relatively low and narrow transverse inclined portion 2i), it is to be noted that several modified plates il should be provided with each complete set of the improved equipment. One of the tracer plates il would preferably be formed substantially as shown in Figs. l and 3, with the inclined portion 2li relatively low and extending at an angle of approximately twenty degrees relative to the anterior area i8. Another of these tracer plates for high cusp teeth would have about one and one-half millimeter or more vertical offset between the anterior and posterior areas IS, i9, and the inclination of the intervening portion 20 would be approximately forty-ve degrees. Still another of these plates il would preferably be formed as shown in Figs. 9 and l0, wherein the anterior and pdsterior areas i8, i9 lie in the same horizontal plane and are merely separated by a slight transverse groove 23. Other modified plates l1 having different forms of dividing lines or abutments separating the anterior and posterior areas I8, I9, may also be furnished, and in all cases, these plates may be formed of thin sheet metal having smooth tracing surfaces which may be readily coated with any suitable and relatively soft tracing material.

During normal use of my improved dental apparatus as when carrying on the improved process, the bite blocks 23, 2l are formed in the usual manner, and the ridges 22, 26 which are usually formed of wax, are applied thereto. The dentist must then select a lower tracer plate Il which ts the anatomical conditions of the particular patient. The upper pin supporting plate i6 should then be applied to the bite block 23 by embedding the side projections 2l thereof in the wax of the ridges 22; and the lower tracer plate il should likewise be applied to the lower bite block 2l and to the ridges 26 thereof. After the plates it, il' have been thus properly applied to the bite blocks, the apparatus may be installed in the patients mouth and the tracer pin lll should be adjusted so as to cause the point thereof to engage the anterior area I8 of the lower plate il. The tracer pin lll should then also be adjusted relative to its supporting block l5 so as to properly position the mandible 28 relative to the maxilla i so as to definitely determine the proper height of the teeth which should be used. When the proper stopping place of the mandible relative to the maxilla has been thus determined, the patient should be requested to trace a Gothic arch 38 upon the anterior area i8, as indicated in Fig. 3. This having been done, the dentist should adjust the pin I4 rearwardly as indicated by the line :it of Fig. 3 until the point of the pin reaches the lower edge of the inclined portion 2S, while the patient is holding the mandible in extreme retrusive position. The patient should thereafter be requested to trace another Gothic arch 39 upon the lower plate il, this arch 3Q having its apex at the line of division between the areas i8, i9, and having its arc portions extending up the incline and onto the uppermost posterior tracing area i9. The arch 39 will then confirm the true centric, and the inclined plane will thereafter guide the tracing pin to the exact apex of the arch in the act of closing to lock the bite plates together for transferring them to the articulator. For patients who cannot make satisfactory Gothic arch tracings, the tracer pin i4 should be adjusted to the center of the area I8 of the tracer plate l'l, and by protruding and retruding the mandible, it will be possible to adjust the tracer pin rearwardly until when it is resting against the foot of inclined plane, or in the groove in the flat plate, whereupon the mandible can only cause tracings to be made upward on the inclined plane or on the anterior tracing area I9, which will confirm the true centric bite.

After the centric and vertical relation has been thus established, the dentist may provide spacer blocks #i2 such as shown in dot-and-dash lines in Fig. 2, and having positioning projections engaging recesses 4| in the side ridges 22, 26, these vblocks i2 serving to permit proper positioning of the bite blocks after they are removed from the patients mouth. The spacer blocks should preferably be made from a plastic material such as plaster of Paris. Where it is desirable to obtain a record of the mandible to the maxilla in the protruded or lateral bites, for determining the inclination of the condyle paths, the spacer locking blocks made for the centric bite should be carefully removed from the trial plates and preserved for mounting the plates on the articulator, and new spacer blocks should be made with the bite closed in the protrusive or lateral bites. These spacer blocks may be used to adjust the degree plates on the articulator to the normal condyle inclinations. The bite blocks with the tracing apparatus therein may thereafter be mounted in centric occlusion to an articulator to construct the final dentures, and in case it becomes desirable to remove the upper assemblage without destroying the bite rims, the tracer pin I4 together with its adjusting mechanism, may be bodily removed from the upper supporting plate i6 in the manner shown in plate and the supporting plate iti can be readily removed by heating with a small gas flame. The spacing blocks i2 cooperating with the recesses lli, will thereafter properly position the upper and lower bite blocks without the aid of the pin M, and the pin lll together with its adjusting screw 3d and guide rod 35, may be readily reapplied to the plate l by merely inserting the ends of the elongated elements in the notches of the iianges 32, 33, while the head 29 of the block i5 is inserted through the enlargement 37 ofthe slot 3l.

It will thus be noted that the improved method and apparatus, provide simple but highly eii'lcient means for determining both the correct vertical stopping point between the mandible and the maXilla, and also provide for rapid determination of the true centric bite. In cases Where there is considerable play between the condyles and the glenoid fossae, or where for any other reason the patient may be unable to trace a denite Gothic arch upon the anterior area I8 of the lower tracer plate il, special procedure may be necessary. However, if the mandible is retruded as far as possible and is held firmly while the tracer pin i4 is adjusted rearwardly as indicated by line @0 of Fig. 3, until the pin I4 reaches the lower edge of the inclined portion 26, from which point, if the mandible was fully retruded, definite tracings will be made by any movement of the mandible toward the rear. If lateral movements can be made with the mandible from this point, a Gothic arch will be traced on the inclined abutment. From this it is obvious that in cases where the patient is not able to trace satisfactory Gothic arch tracings on the anterior plate area I8, it is possible to secure accurate informations of the true centric relation by adjusting the tracer pin I4 rearwardly until it reaches the transverse groove or inclined portion 2U, from which point any movement must be to the rear if the true centric relation has been established. As previously indicated, the height of the cusps and the form of anatomical teeth that are to be used, will determine the height and degree of the inclination that should be used in the tracer plate, where check bites are to be taken to determine the degree of inclination in the condyle paths. In cases where it is desirable to use non-anatomical teeth without cusps, a tracer plate I1 such as shown in Figs. 9 and 10 and where the anterior tracing area I8 and the posterior area i9 are on the same plane, should be used. It has also been found that any dentists will readily become accustomed to the use of the new method and apparatus, and that truly accurate results are always obtainable. The pin adjusting mechanism or" Figs. 6, 7 and 8 may obviously be substituted for that shown in Figs. 1, 2 and 5, and other modiiications of the apparatus may obviously be introduced without departing from the spirit of the present invention. 'Ihe entire apparatus is extremely simple and compact and the horizontal adjustment of the pin lll may be effected from the exterior of the patients mouth. rlhe assemblage may, moreover be produced at moderate cost, and has been found to actually produce results which are far superior to those produced with similar prior equipment.

Attention is also directed to the fact that it is not necessary with my improved apparatus, for the patient to be able to trace a Gothic arch in order to enable the dentist to determine centric position, since proper initial positioning of the tracer pin against the abutment will cause the pin point to assume centric position when biting takes place. It is moreover possible with my present improvement, to provide for extra-oral tracing and adjustment of the pin, instead of intra-oral operation, as shown, by merely providing forward extensions on the screw 34 and tracing plate i9 which may be located externally of the patients mouth. The use of eXtra-oral recording apparatus is however well known to those skilled in the art who will readily understand that my present invention is also adaptable for such recording.

It should be understood that it is not desired to limit this invention to the exact details of construction or to the precise mode of use of the apparatus herein shown and described, for various modications within the scope of the claims may occur to persons skilled in the art.

I claim:

1. In combination with bite blocks fitting a patients jaws, a threaded rod journalled for rotation on one of said blocks and being rotatable from the iront externally of the patients mouth, a tracer pin movable along said block by said rod and being guided for sliding movement relative to said block, and a tracer plate supported by the other of said blocks in the Zone of action of said 2. In combination with bite blocks tting a patients upper and lower jaws, a plate secured to the upper block and having an elongated slot therein, a threaded rod journalled in said upper block and being rotatable from the front externally of the patients mouth, a tracer pin movable along said plate by said rod and being guided for sliding movement in said slot, and a tracer plate supported by the lower of said blocks in the zone of action of said pin.

3. In combination with bite blocks tting the upper and lower jaws of a patient, an upper plate supported by the upper bite block and having a guide thereon, a threaded rod detachably journalled on said plate, a threaded block coacting with said rod and guide and being movable along said guide by rotation of said rod, a tracer pin carried by said threaded block, and a lower tracer plate supported by the lower bite block in the Zone of action of said pin.

4. In combination with bite blocks fitting the upper and lower jaws of a patient, an upper plate secured to the upper bite block and having a guide slot therein, a threaded rod journalled on said plate and being rotatable from the front externally of the patients mouth, a threaded block coacting with said rod and slot and being movable along the latter by rotation of said rod, a tracer pin carried by and being vertically adjustable relative to said threaded block, and a lower tracer plate secured to the lower bite block in the zone of action of said pin.

5. In combination with upper and lower bite blocks fitting the jaws of a patient, an upper plate secured to the upper bite block and having a guide slot therein and ears at the ends of said slot, a threaded rod journalled for rotation within said ears and being rotatable from the front externally of the patients mouth, a supporting block threaded for coaction with said rod and coacting with said slot, said rod and supporting block being detachable as a unit from said upper plate, a tracer pin adjustably suspended from said supporting block, and a lower tracer plate secured to the lower bite block in the zone of action of said pin.

JAMES SORENSON. 

